Image forming apparatus

Abstract

The image forming apparatus is arranged accurately to keep a constant distance between the surface of the photosensitive element and a charging device. The charging device is composed as a part of an integrated unit with another device which is located around the surface of the photosensitive element. When the unit is mounted on the main body of the apparatus, the charging device is in contact with a positioning means which is provided on the image forming apparatus.

What is claimed is: 
     
       1. An image forming apparatus comprising: a main body;   a photosensitive element mounted to said main body;   a charging means for forming an electrostatic latent image on the photosensitive element;   a support means removably mountable in said main body and movably supporting the charging means by means permitting the size of a gap between the surface of the photosensitive element and the charging means to vary; and   a positioning means which contacts the charging means and positions the charging means at a constant distance from the surface of the photosensitive element when the support means is mounted on said image forming apparatus,   wherein said means permitting the size of the gap to vary comprises a slot in said suport means and a projection of said charging means which slidably fits in said slot, said slot extending toward said photosensitive drum.   
     
     
       2. The image forming apparatus according to claim 1, wherein said support means is a cleaning unit. 
     
     
       3. The image forming apparatus of claim 1 wherein said positioning means comprises a projected member.